Vultures await warm weather

By DIANE VANCE | Apr 26, 2013

Jefferson County naturalist Therese Cummiskey said the turkey vultures that congregate at the water tower on South B Street are waiting for the weather to warm up before migrating north. Parts of Iowa and Minnesota were blanketed with snow earlier this week.

Large black birds roosting on Fairfield’s water tower at South B Street and East Adams Avenue in the evenings the past few months have piqued the curiosity of many in the community.

Turkey vultures are native to the U.S. and spend time in Iowa from about February/March through fall, Iowa’s warmer months, said Diane Porter, Fairfield’s resident ornithologist.

“Vultures are benign birds and roost communally,” said Porter.

Vultures can be seen year-round in the southern United States, and into South America. They migrate north as the weather warms, reaching into the southern parts of Canada, said Therese Cummiskey, Jefferson County naturalist.

“Vultures are one of my favorite birds,” said Cummiskey. “They are beautiful to watch gliding, and one of their defenses is vomiting.

“This is the first time I can remember seeing them roost on the water tower. I’ve also noticed them on a radio tower behind Best Western Fairfield Inn.”

Why the vultures have adopted the water tower this season is not clear.

“It’s a safe, high place, vultures like to be warm and roost together,” said Porter. “We have a place on our property where 20 to 30 vultures gather in a wooded canyon and have been for several years.”

Cummiskey has a guess about the vultures in Fairfield this year.

“I think they are waiting here until it’s warmer up north,” she said. “My mom lives in southern Minnesota and just got 6.5 inches of snow!”

Spreading their wings in the sun is characteristic of vultures.

“I imagine it feels good to have the sun on their feathers and warms them,” said Porter. “Vultures are not a nuisance, they don’t steal chickens or other live animals; they eat dead flesh.”

Other characteristics of vultures are the circling and gliding.

“You won’t usually see vultures flapping around,” said Porter. “They find air currents and soar, riding thermals, like an elevator. They fly up high and glide down.”

Even in migration, vultures don’t flap often, but ride the air currents, said Porter.

“Vultures rise on the currents, and up high they can see other columns of vultures and set their wings, gliding over on the next thermal to join them,” she said. “This also applies to looking for food. Vultures can see other vultures circling an area and will join in.”

Porter said most bird species have a poor sense of smell.

Vultures have a keen sense of smell and when circling above a woods or field, they are honing in on a smell that tells them a dead carcass is to be found.

“And contrary to popular belief, vultures don’t like rotting flesh,” said Porter. “They prefer fresh kill, a day or two old. They do a great service for us, cleaning up dead animals.”

Porter referred to The Cornell Lab of Ornithology website, All About Birds, at www.allaboutbirds.org.

“Vultures eat carrion, mostly mammals, road kill, but also smaller things such as grasshoppers, snails and dead mayflies,” said Porter. “And down south, vultures will eat dead reptiles, such as snakes and alligators.

“They eat some plant material incidentally, in the intestines of the carrion. They have been known to deliberately eat pumpkins in Ohio. And they will eat coyote poop and cow manure,” said Porter, reading from the website. “Vultures drink water and will eat salt off of salt blocks.

“They prefer fresh carrion, but cannot open thick-skinned animals themselves and wait for coyotes to open the bodies or wait until putrification opens it up.”

Turkey vultures’ Latin name, Cathartes aura, derived from the Greek “katharsis” means to purify or to cleanse, according to Bob Gosford’s Internet blog, The Northern Myth.

One meaning takes the second part to derive from the Latin “aureus” meaning golden, so the full name means “golden purifier.” The other definition takes the second part to derive from the Greek “aura,” meaning breeze, so the full name translates as “cleansing breeze,” Gosford writes from Darwin, Australia.